- optical illusion
The vertical lines distort and appear twisted. Each is made of a series of light and dark paddle shapes.
Try other even Order values from 2 to 12...
To New
# set default screen, pen and turtle values
ResetAll SetScreenSize [400 400] HideTurtle
SetSC Black SetPC Green SetPS 1 PenUp
End
To GridSq :Order :Side
# draw tile at each column x row position
LocalMake "Offset (1+:Order)/2
For (List "Col 1 :Order) [
For (List "Row 1 :Order) [
SetXY :Side*(:Col-:Offset) :Side*(:Row-:Offset)
Tile :Col :Row :Side] ]
End
To Tile :Col :Row :Side
If (Or X<:Side-200 X>200-:Side Even? :Col) [Stop]
If Even? :Row [SetPC [153 204 255]] [SetPC [0 102 153]]
If (Mod :Col 4)=3 [Make "Parity 1] [Make "Parity Minus 1]
SetH :Parity*9
Paddle :Side :Parity Fill Wait Int :Side/10
End
To Paddle :Size :Parity
# draw flag shape, left or right handed
Left :Parity*90 Forward :Size/14 Right :Parity*90 PenDown Repeat 2 [
Forward 1.5*:Size Right :Parity*135 Forward 0.702*:Size Right :Parity*90
Forward 0.5*:Size Left :Parity*45 Forward 0.65*:Size] PenUp
Right :Parity*90 Forward :Size/14 Right :Parity*90 # r2c
End
To Even? :Num
# return 'true' if Num even, else return 'false'
If (Mod :Num 2)=0 [Output "True] [Output "False]
End
To Go :Order
New SetSC [204 153 153]
Make "Order 3+2*:Order
GridSq :Order Int 420/:Order
End